I am sorry for the misunderstanding and I will try to publish a new release this weekend. I had almost the same code as you just posted, the correct code will be this:
// You don't need to clone the input image.//var dest = input.Clone(); using (var src = input.Clone()) { // There is an implicit cast from an integer to a Percentage. src.Colorize(new MagickColor(hexaColor), 100); using (var mask = input.Clone()) { mask.ColorSpace = ColorSpace.GRAY; // Do not negate the image because the command line does that internally and the -negate is there to// 'double negate' (make it normal). The Magick.NET codes skips that part.// mask.Negate();// This will be the new property that works differently from ClipMask input.Mask = mask; input.Composite(src, Gravity.Center, CompositeOperator.Blend, "100,0"); input.Write("imgOutput.jpg"); } }